Path: utzoo!attcan!uunet!cbmvax!sterling
From: sterling@cbmvax.UUCP (Rick Sterling QA)
Newsgroups: comp.sys.amiga
Subject: Re: Atalk III 1.0e
Message-ID: <5707@cbmvax.UUCP>
Date: 17 Jan 89 16:48:06 GMT
References: <470@infohh.rmi.de> <6818@killer.DALLAS.TX.US>
Reply-To: sterling@cbmvax.UUCP (Rick Sterling QA)
Organization: Commodore Technology, West Chester, PA
Lines: 51

In article <6818@killer.DALLAS.TX.US> elg@killer.DALLAS.TX.US (Eric Green) writes:
> in article <470@infohh.rmi.de>, shimoda@infohh.rmi.de (Markus Schmidt) says:
> > If the uploader handled the file correct there should be no problem
> > with chopping. According to Chuck Forsberg you may pad either with NUL
> > or CMP_EOF, and there is no reason for not using CMP_EOF when the last
> > byte of the file is NUL. 
> > Of course the receiver may only chop those PADs that match the last byte
> > in the transfer and not mixed 00 and 1A.
> 
> Let's say that your file length is an exact multiple of 128 bytes.
> Further, let's say that your file ends with fifteen NUL characters.
> Xmodem will not create an extra empty padding block. Thus an
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> autochopper will chop off 15 bytes of your file.
> 
> That's just one example of why Xmodem is brain-dead for use with
> non-CP/M systems. I personally use Batch Ymodem or Zmodem whenever
> possible, just to bypass those problems.
> 
> --
> Eric Lee Green    ..!{ames,decwrl,mit-eddie,osu-cis}!killer!elg
>           Snail Mail P.O. Box 92191 Lafayette, LA 70509              
> Netter A: In Hell they run VMS.
> Netter B: No.  In Hell, they run MS-DOS.  And you only get 256k.

 According to my reading of the protocol it should create the extra padding
 block with ^Z's ... This is how I implemented it in several term progs in
 the past....

 1. If file is a multiple of 128 bytes and does not end with $00 or $1A
    send file as is.
 2. If file is a multiple of 128 bytes and ends with $00 then pad extra 
    block with $1A
 3. If file is a multiple of 128 bytes and ends with $1A then pad extra 
    block with $00
 4. If file is not multiple of 128 bytes and ends with $00 then pad to end
    of block with $1A
 5. If file is not multiple of 128 bytes and ends with $1A then pad to end
    of block with $00
 6. If file is not a multiple of 128 bytes and does not end with $00 or $1A
    then pad to end of block with $1A
 
    No 'munged' files ;-)

  - Rick -

-- 
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   Rick Sterling             COMMODORE AMIGA TEST ENGINEERING
      N2CGI                  UUCP  {allegra,rutgers}!cbmvax!sterling 
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